NEW YORK, Feb. 13 /PRNewswire/ -- Standard & Poor's will make the following changes to the S&P 500, S&P MidCap 400 and S&P SmallCap 600 indices:

• Diamond Offshore Drilling Inc. (NYSE: DO) will replace Weatherford International Ltd. (NYSE: WFT) in the S&P 500 on a date to be announced. Weatherford is in the process of redomesticating to Switzerland, rendering it ineligible for continued inclusion in the S&P 500.

• S&P SmallCap 600 constituent Panera Bread Co. (Nasdaq: PNRA) will replace ArvinMeritor Inc. (NYSE: ARM) in the S&P MidCap 400, and CommVault Systems Inc. (Nasdaq: CVLT) will replace Panera Bread in the S&P SmallCap 600 after the close of trading on Friday, February 20. As of today's close, ArvinMeritor had a market capitalization below $75 million, ranking it 400th in the index.

• Iowa Telecommunications Services Inc. (NYSE: IWA) will replace BankAtlantic Bancorp Inc. (NYSE: BBX), and Almost Family Inc. (Nasdaq: AFAM) will replace Basset Furniture Industries Inc. (Nasdaq: BSET) in the S&P SmallCap 600 after the close of trading on Friday, February 20. As of today's close, BankAtlantic and Bassett Furniture had market capitalizations of approximately $18 million and $21 million respectively, ranking them 600th and 599th in the index.

Standard & Poor's will monitor these transactions, and post any relevant updates on its website: www.standardandpoors.com.

Diamond Offshore provides contract drilling services to the energy industry, and is also engaged in deepwater drilling. Headquartered in Houston, TX, the company will be added to the S&P 500 GICS (Global Industry Classification Standard) Oil & Gas Drilling Sub-Industry index.

Panera Bread operates retail bakery-cafes. Headquartered in Richmond Heights, MO, the company will be added to the S&P MidCap 400 GICS Restaurants Sub-Industry index.

CommVault Systems is a provider of data management software applications and related services. Headquartered in Oceanport, NJ, the company will be added to the S&P SmallCap 600 GICS Systems Software Sub-Industry index.

Iowa Telecommunications Services is a provider of wireline local exchange telecommunications services to residential and business customers in rural Iowa.